There are a lot of products out there that are flat-out ripoffs but YouTube teardown artiste Markus Fuller recently found a real doozy when he spent £500 (~$USD 700) on a rechargeable battery pack that was in reality approximately $30 worth of batteries stuffed into a big case. His teardown video of the battery and his gradual realization that he’d been ripped off is one of the most amusing things you’ll see on YouTube this week.

“Here I take apart a £500 rechargeable battery for the Nagra IV (6) digital recorder to find Lithium polymers inside worth about £22.50,” he writes on his YouTube page. “I think it’s an expensive waste to purchase the box and circuit everytime a battery fails especially as the cell pack simply unplugs, and according to the Nagra website Lithium-Ion battery packs will last for between 500 and 1,000 charge cycles. Don’t get me wrong Nagra makes quite incredible top quality gear but I was somehow expecting some very clever tech in the battery box considering it’s price.”

Amusingly, he notes that the back of the battery says “DO NOT OPEN,” even though there’s nothing really all that dangerous inside it. What’s more, it’s clear that the “battery” could have housed a lot more batteries inside but most of it is just padded with a foam packaging sponge.